Reversing absolute phase

Lewm, I agree under the present circumstances.

A manufarturer's choice to include polarity reversal is based on budget and the sonic dgredation involved in the extra stage that most designs would require, and that of the switch to control it.

Piedpiper, I agree about the degradation. I had a Millennium preamp made by Siltech, with a remote switch to invert. I noticed that the best sound was to invert the speakerwires at the speaker but not on the preamp. It turned out to be an inverting preamp and did use another stage to allow inverting. I was hearing the loss in using the inverted setting. As you say some designs could easily provide this. All line stages with parallel outputs even if they just use a transformer could provide it without an additional stage. Parafeed designs could also.

Would it not be great were recording engineers to chose one polarity and stick to it? All you would have to do would be to decide which you preferred with your speaker connections and stick too it.

were the world that simple.

Tbg, If you do agree with my statement above, then there is no way that recording engineers could "agree to one polarity and stick to it". I'm not absolutely certain that my assumption is correct (regarding the fact that on the recording side, selecting polarity is not possible due to multiple instruments, multiple mikes, the effects of mixers, room effects, etc), but that's what I wrote. True, the recording engineer could decide whether or not to flip a polarity switch, much as we do on the other end of the repro chain, but he's only altering the polarity of a bunch of mixed sources that in and of themselves most likely are of non-uniform polarity.